1. Field of the Invention
Embodiments of the present invention relate in general to the field of portable computing devices and, more particularly, to an improved method and apparatus for the management of power states in a portable computing system.
2. Description of the Related Art
In recent years, there has been a rapid expansion of the use of personal computing devices, particularly those adapted for portable use. Personal computing devices include lightweight portable computers, such as handheld computers, “palmtops”, and personal digital assistants (PDAs), that typically weigh one to three pounds. These personal computing devices generally provide some combination of personal information management, database functions, word processing, and spreadsheets as well as voice memo recording, wireless e-mail, and wireless telephony functions.
Since personal computing devices are generally battery powered, it is important to maximize battery life to enhance the usability of such devices. It is also desirable, however, to provide users with rapid access to software applications. Some personal computing devices, such as PDAs, provide “instant on” functionality, but do so by draining the battery during the “off” state. It is possible to simulate “instant on” in laptop computers; however it is still necessary to drain battery power in the “off” state. Prolonged periods of inactivity result in the need to shut the computer off completely, thereby requiring the execution of a full or abbreviated reboot procedure.
As will be understood by those of skill in the art, it is highly desirable to minimize the time needed to place the device in a fully operational state. At the same time, however, it is important to minimize the amount of batter power needed to maintain the device in a state that gives the user the perception that the device is instantly activated. In view of the foregoing, there is a need for a method and apparatus that is capable of providing effective power management for a personal computing device, while minimizing the latency experienced by users.